The 10 most valuable companies in the U.S. by market capitalization:
Apple Inc., $337 billion
Exxon Mobil Corp., $331 billion
Microsoft Corp., $203 billion
International Business Machines Corp., $194 billion.
Chevron Corp., $181 billion.
Google Inc., $178 billion.
Procter & Gamble Co., $171 billion.
Berkshire Hathaway Inc., $168 billion.
Wal-Mart Stores Inc., $168 billion.
AT&T Inc., $165 billion.
Johnson & Johnson, $165 billion.
Source: FactSet